Electric discharge device



March 14, .1933. D. LELY ELECTRIC DISCHARGE DEVICE Filed Aug. 31, 1927 INVENTOR DIRK LELY ATTORNEY Patented Mar. 14, 1933 UNITED STATES PATENT OFFICE DIRK LELY, OF EIND'HOVEN, NETHERLANDS, ASSIGNOR TO RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE ELECTRIC DISCHARGE DEVICE Application filed August 31, 1927, Serial No. 216,613, and in the Netherlands November 5, 1926.

This invention has reference to an electric discharge device having three electrodes enclosed within a gas tight envelope and having the leading-in wires of the control grid and the anode spaced apart as far as possible at the points where they pass through the envelope.

This spacing of the leading-in wires of the said electrodes serves to eliminate the capacity which exists between closely spaced leading-in wires of the control grid and the anode. This capacity can reach an appreciable value, and causes in addition an undesired coupling between the grid circuit and the anode circuit.

Discharge devices using the particular arrangement of electrode leads mentioned above have the disadvantage that the customary contacts are not mounted together on the base. Instead the anode contact is at a point of the tube which is far away from the other contacts, and therefore such discharge devices when used in a receiver unit for wireless telephony and telegraphy do not permit employment of the normal i-pin bases.

The present invention provides a way by which, regardless of the. particular point on the wall of the envelope at which the leadingin wire of the control grid or of the anode is brought out allows the contact of the leadingin wire that is not led out through the usual base, to be mounted on the base.

According to the invention the. base of the device has also fitted on it a contact pin for the electrode of which the leading-in wire is not brought out through the base. The object of the invention then is to utilize the usual 4 pin base and still reduce capacitive efiects between anode and grid leads to a minimum.

The device has two terminals one of which is connected to a contact pin in the 4 pin base whereas the other is connected to the leadingin wire that is not led out through the base. The terminal connected to the contact pin may be mounted, for example, on the side of the base. The leading-in wire for the control grid may be led out through the base on one end of the envelope and the leading-in wire for the anode may be led out through the opposite end or tip of the envelope or bulb. The terminals are not essential, but are preferred, although a single'lead-in wire may directly connect the anode with its contact pin in the base without the use of the terminals.

The invention will be more clearly under stood by reference to the accompanying drawing which illustrates the invention. Referring to the drawing, 1 designates a glass envelope and having on the bottom end a base 2 with the customary contact pins 8. The anode leading-in wire 3 is connected to a terminal at the other end or top of the glass envelope. The electrical connection between the anode and the anode contact pin in the base is established by a conductor 5 which is shown as being outside the envelope. The leading-in wire 4 for the grid and the leadingin wires for the filament are led out through the base 2. The anode contact pin in the base is not directly connected to the corresponding electrode by a leading-in wire passing through the base as is customary but is connected to a terminal 7 which in the embodiment shown is fitted on the base 2 and which in turn is connected by the conductor 5 to the anode terminal 6.

Although the drawing discloses the anode lead-in wire passing through the tip of the bulb, it is clear that the grid lead-in may pass through the tip and the anode lead-in wire will then pass through the base.

It is obvious further that the circuit connection to the anode may be established by connecting directly to the terminal 6, the conductor 5 being omitted. Also the invention will function equally well if only one of the terminals shown is used and that one terminal may be either on the base or the tip of the bulb.

What I claim is:

1. An electron discharge device comprising an evacuated envelope, a plurality of electrodes contained therein, a base sealed to said envelope and provided with a plurality of contact pins, a terminal projecting from the top of the envelope opposite to the base, a conductor connected between said terminal and one of said electrodes, a second terminal von the base and a conductor connected between said second terminal and one of said pins, lead-in conductors within the myefope passi through the base and con l necfledbetw n e remaining electrodes and the n L -mjgmdactor 1 ah. a 61* .3 migggandseconfl r zc en zficmtedenvetofic 51 m a eiectrodes conta 'edflierein, a base Za'mam said envelope and wmu.

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